Crazy Paving Sign

characterized by
- scattered or diffuse
- ground-glass attenuation with
- superimposed interlobular septal thickening and
- intralobular lines

Alveolitis
Diagram shows inflammation (red ) in the walls of the alveoli with thickening of the interlobular septa (maroon) . The increased density in the interalveolar septa and interlobular septa results in a ground glass opacity with and crazy paving appearance on CT scan
Ashley Davidoff TheCommonVein.net
lungs-0736a

Crazy Paving ARDS
Ashley Davidoff TheCommonVein.net ARDS-crazy-paving

Causes
- Infection
  - Pneumocystis carinii pneumonia
    - severely immunocompromised patient
- Inflammatory
  - Sarcoidosis
  - NSIP
  - Organizing Pneumonia
- Neoplasm
  - Mucinous bronchioloalveolar carcinoma
- Circulatory
  - Hemorrhage
- Idiopathic
  - Alveolar proteinosis
- Inhalational
  - Lipoid pneumonia
- Systemic Disease

The Secondary Lobule

This image is a panoramic view of the lung showing almost rectangular secondary lobules surrounded by interlobular septa (cream borders) The distal bronchioles (teal) and pulmonary arteriole (royal blue are shown in the centre of a lobule in the right lower corner. The branches of these two structures are shown in the secondary lobule with the acinar airways shown in teal and the presumed course artistically inferred in royal blue. Within the interlobular septa (light pink) remnants of the pulmonary venules (red – inferred) and lymphatics (yellow inferred) course going in the opposite direction to the arteriole and the airways.
Keywords:
lung pulmonary alveoli alveolus secondary lobule interlobular septa vein lymphatic histology interstitium interstitial normal
Courtesy of: Armando Fraire, M.D. Ashley Davidoff TheCommonVein.net

Thickened Interlobular Septa due to Inflammation – Acute Eosinophilic Pneumonia

Interlobular Septal Infiltration with Eosinophils and Inflammatory Exudate – Thickening of the Interlobular Septa – Crazy Paving Kerley B lines
The diagram shows the thickened septum surrounding the secondary lobule due to an inflammatory process, cellular infiltrate and congestion of the venules and lymphatics in the septum (a) . An anatomic specimen of a secondary lobule from a patient with thickened interlobular septa is shown in c and overlaid in d. CT of the lungs in a patient with acute eosinophillic pneumonia shows thickened interlobular septa and centrilobular nodules and the thickened septa are overlaid in red (e).
Ashley Davidoff MD The CommonVein.net
lungs-0761

Anthracotic Lung
Anthracosis – Note the accumulation of carbon particles within the lymphatics along the interlobular septa, outlining the secondary lobules. The carbon particles are inhaled from an anthracotic urban environment. Courtesy Ashley Davidoff MD. TheCommonVein.net 32291 key words lung interlobular septum septa secondary lobule pulmonary lobule intertstitium interstitial gross pathology carbon

Infection

P carinii pneumonia in a 32-year-old man with acquired immunodeficiency syndrome. (a) High-resolution CT scan shows areas of ground-glass attenuation with intralobular lines. (b) Photomicrograph (original magnification, 400; Grocott stain) of a specimen obtained with bronchoalveolar lavage shows alveolar exudates that contain cystic forms of P carinii (arrows).
Rossi, S.E et al “Crazy-Paving” Pattern at Thin-Section CT of the Lungs: RadiologicPathologic Overview Radiographics Volume 23 – Number 6, 2003

Inflammatory Diseases

ARDS

77F with Aspiration Pneumonia ARDS and Crazy Paving

Inflammation
- Sarcoidosis
  Sarcoidosis in a 25-year-old asymptomatic
  man. High-resolution CT scan shows scattered bilateral
  areas of ground-glass attenuation associated with inter and intralobular lines.
  Rossi, S.E et al “Crazy-Paving” Pattern at Thin-Section CT of the Lungs: RadiologicPathologic Overview Radiographics Volume 23 – Number 6, 2003
  
  Amyloidosis
  
  Diffuse alveolar-septal amyloidosis
  CT scan in the axial projection at the base of the lungs show many features of amyloidosis including lung nodules (white arrowheads) and infiltrates (b), and diffuse deposition within the alveolar septa (red arrowheads, c) and centrilobular nodules(yellow arrow c)
  Ashley Davidoff MD Boston Medical Center
  TheCommonVein.net septal-amyloidosis-001b
  
  NSIP
- Methotrexate-induced NSIP in a 41-year-old woman with rheumatoid arthritis who presented with dyspnea and decreased diffusing capacity of the lungs for carbon monoxide (Dlco). (a) High-resolution CT scan shows
  scattered ground-glass attenuation and thickened inter- and intralobular lines (arrow). (b) Photomicrograph (original
  magnification, 400; hematoxylin-eosin stain) of a specimen from lung biopsy shows patchy interstitial fibrosis, expansion of the interstitium by chronic inflammatory infiltrates, and reactive hyperplastic type II pneumonocytes (arrow), findings consistent with NSIP induced by the pulmonary toxic effects of methotrexate.
  Diffuse mucinous bronchioloalveolar carcinoma in a 78-year-old man. (a) High-resolution CT scan
  shows a bilateral crazy-paving pattern and centrilobular nodules. (b) Photomicrograph (original magnification,
  400; hematoxylin-eosin stain) of a specimen from open lung biopsy shows replacement of the alveolar epithelium
  by epithelial neoplastic cells with abundant intracytoplasmic mucin (arrows).
  Rossi, S.E et al “Crazy-Paving” Pattern at Thin-Section CT of the Lungs: RadiologicPathologic Overview Radiographics Volume 23 – Number 6, 2003
Neoplasm
Diffuse mucinous bronchioloalveolar carcinoma in a 78-year-old man. (a) High-resolution CT scan
shows a bilateral crazy-paving pattern and centrilobular nodules. (b) Photomicrograph (original magnification,
400; hematoxylin-eosin stain) of a specimen from open lung biopsy shows replacement of the alveolar epithelium
by epithelial neoplastic cells with abundant intracytoplasmic mucin (arrows).
Rossi, S.E et al “Crazy-Paving” Pattern at Thin-Section CT of the Lungs: RadiologicPathologic Overview Radiographics Volume 23 – Number 6, 2003

Primary lung adenocarcinoma in a 54-year-old man with hemoptysis. (a) Posteroanterior chest radiograph shows a centrally located mass adjacent to an area of diffuse ground-glass opacity in the right upper lobe. Note
the air trapping in the lung base. (b) CT scan shows typical crazy-paving ground-glass attenuation associated with
septal thickening surrounding the mass, which is perihilar. Adenocarcinoma with surrounding pulmonary hemorrhage was confirmed at surgery
Rossi, S.E et al “Crazy-Paving” Pattern at Thin-Section CT of the Lungs: RadiologicPathologic Overview Radiographics Volume 23 – Number 6, 2003
Circulatory Disorders
- Hemorrhage
- Acute diffuse pulmonary hemorrhage in a 53-year-old woman with systemic lupus erythematosus and
  massive hemoptysis. (a) High-resolution CT scan shows geographic areas of ground-glass attenuation with interlobular septal thickening. (b) Photomicrograph (original magnification, 250; hematoxylin-eosin stain) shows acute intraalveolar hemorrhage.
  Rossi, S.E et al “Crazy-Paving” Pattern at Thin-Section CT of the Lungs: RadiologicPathologic Overview Radiographics Volume 23 – Number 6, 2003
- CHF Rare
- CHF and Crazy Paving
  44-year-old man with dyspnea and cough diagnosed as having congestive heart failure. CT of the thorax shows diffuse, multifocal, patchy, ground-glass opacities (arrow).
  Şentürk A, et al A Rare Cause of Crazy-Paving and Mediastinal Lymphadenopathy: Congestive Heart Failure Journal of Clinical Imaging Science 3(1):30 July 2013
Idiopathic
- Alveolar Proteinosis
- Alveolar proteinosis in a 37-year-old woman with a nonproductive cough and dyspnea. (a) Posteroanterior chest radiograph shows bilateral reticular areas of increased opacity, which occur predominantly in the lower
  zones. (b) High-resolution CT scan shows diffuse geographic ground-glass attenuation with superimposed intra- and
  interlobular septal thickening (arrowhead). Note the polygonal appearance, which represents the secondary pulmonary lobule. (c, d) Photomicrographs (original magnification, 400; hematoxylin-eosin [c] and periodic acid–Schiff
  [d] stains) of a specimen from transbronchial biopsy show alveolar spaces filled by a dense, eosinophilic, granular
  proteinaceous material () that is positive for periodic acid–Schiff stain.
  Rossi, S.E et al “Crazy-Paving” Pattern at Thin-Section CT of the Lungs: RadiologicPathologic Overview Radiographics Volume 23 – Number 6, 2003
Inhalational
- Lipoid pneumonia
- Lipoid pneumonia in a 64-year-old woman with a 20-year history of scleroderma who presented with progressive dyspnea and a dry cough. (a) Posteroanterior chest radiograph shows bilateral, asymmetric, scattered areas of increased opacity in the air space, which have a predominantly perihilar and basal distribution. (b) High-resolution CT scan shows geographic ground-glass attenuation in association with interlobular thickening and intralobular lines (arrow). The results of bronchoalveolar lavage and transbronchial biopsy were nondiagnostic. (c) Photomicrograph (original magnification, 250; hematoxylin-eosin stain) of a specimen from open lung biopsy shows numerous lipid-laden macrophages that fill and distend the alveoli (arrow) and interstitium.
  Rossi, S.E et al “Crazy-Paving” Pattern at Thin-Section CT of the Lungs: RadiologicPathologic Overview Radiographics Volume 23 – Number 6, 2003
Systemic Disease

CHF – Alveolar Edema
CT scan shows Diffuse ground glass pattern with thickening of the interlobular septa and manifesting as crazy paving pattern
Ashley Davidoff MD

Crazy-paving sign. Axial CT of the chest shows thickening of the intralobular and interlobular septa with a superimposed background of ground-glass opacity in a patient with pulmonary alveolar proteinosis.
Source
Signs in Thoracic Imaging
Journal of Thoracic Imaging 21(1):76-90, March 2006.

CRAZY PAVING IN ILD
Crazy paving in ILD is a CT feature of interstitial lung disease and is characterised by diffuse ground glass caused by a combination of interlobular septal and intralobular septal thickening resulting well demarcated patchy densities in the lungs.

Idiopathic

57-year-old female with progressive dyspnea.

CRAZY PAVING – NORMAL SIZED HEART
Ashley Davidoff MD

References and Links

Rossi, S.E et al “Crazy-Paving” Pattern at Thin-Section CT of
the Lungs: RadiologicPathologic Overview Radiographics Volume 23 – Number 6, 2003
TCV
- Cases
  - 027Lu Crazy Paving ARDS vs PCP

The Secondary Lobule

Infection

Idiopathic

Inhalational

Systemic Disease

Idiopathic

References and Links